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using System; |
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using Discord.Net.Serialization; |
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namespace Discord.Net.Serialization |
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{ |
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/// <summary> |
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/// Defines a type which may be either undefined, null or an instance of a |
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/// value. |
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/// </summary> |
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/// <typeparam name="T"> |
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/// The type which is contained |
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/// </typeparam> |
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public struct Optional<T> |
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{ |
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private readonly T _value; |
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/// <summary> |
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/// Gets the inner value of this <see cref="Optional{T}"/> if present. |
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/// </summary> |
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/// <returns> |
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/// The value inside this <see cref="Optional{T}"/>. |
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/// </returns> |
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/// <exception cref="InvalidOperationException"> |
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/// This <see cref="Optional{T}"/> has no inner value. |
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/// </exception> |
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public T Value |
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=> !IsSpecified |
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? throw new InvalidOperationException( |
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"This property has no value set.") |
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: _value; |
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/// <summary> |
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/// Gets if this <see cref="Optional{T}"/> has an inner value. |
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/// </summary> |
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/// <returns> |
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/// A boolean that determines if this <see cref="Optional{T}"/> has a |
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/// <see cref="Value"/>. |
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/// </returns> |
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public bool IsSpecified { get; } |
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private Optional(T value) |
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{ |
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_value = value; |
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IsSpecified = true; |
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} |
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/// <summary> |
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/// Creates a new unspecified <see cref="Optional{T}"/>. |
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/// </summary> |
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/// <returns> |
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/// An unspecified <see cref="Optional{T}"/>. |
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/// </returns> |
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public static Optional<T> Create() |
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=> default; |
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/// <summary> |
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/// Creates a new <see cref="Optional{T}"/> with the specified |
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/// <paramref name="value"/>. |
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/// </summary> |
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/// <param name="value"> |
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/// Value that will be specified for this <see cref="Optional{T}"/>. |
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/// </param> |
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/// <returns> |
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/// A specified <see cref="Optional{T}"/> with the provided value |
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/// inside. |
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/// </returns> |
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public static Optional<T> Create(T value) |
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=> new(value); |
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/// <summary> |
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/// Gets the <see cref="Value"/> or their <see langword="default"/> |
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/// value. |
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/// </summary> |
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/// <returns> |
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/// The value inside this <see cref="Optional{T}"/> or their |
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/// <see langword="default"/> value. |
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/// </returns> |
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public T GetValueOrDefault() |
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=> _value; |
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/// <summary> |
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/// Gets the <see cref="Value"/> or the default value provided. |
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/// </summary> |
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/// <returns> |
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/// The value inside this <see cref="Optional{T}"/> or default value |
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/// provided. |
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/// </returns> |
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public T GetValueOrDefault(T defaultValue) |
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=> IsSpecified ? _value : defaultValue; |
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/// <inheritdoc/> |
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public override bool Equals(object? other) |
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{ |
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if (!IsSpecified) |
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return other == null; |
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if (other == null || _value == null) |
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return false; |
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return _value.Equals(other); |
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} |
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/// <inheritdoc/> |
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public override int GetHashCode() |
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=> IsSpecified ? _value?.GetHashCode() ?? default : default; |
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/// <summary> |
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/// Returns the inner value ToString value or this type fully qualified |
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/// name. |
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/// </summary> |
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/// <returns> |
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/// The inner value string value or this type fully qualified name. |
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/// </returns> |
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public override string? ToString() |
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=> IsSpecified ? _value?.ToString() : default; |
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/// <summary> |
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/// Creates a new <see cref="Optional{T}"/> with the specified |
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/// <paramref name="value"/>. |
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/// </summary> |
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/// <param name="value">Value to convert</param> |
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/// <returns> |
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/// A new <see cref="Optional{T}"/> with the specified |
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/// <paramref name="value"/>. |
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/// </returns> |
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public static implicit operator Optional<T>(T value) |
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=> new(value); |
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/// <summary> |
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/// Gets the inner value. |
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/// </summary> |
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/// <param name="value"> |
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/// Value to convert |
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/// </param> |
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/// <returns> |
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/// The inner value. |
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/// </returns> |
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public static explicit operator T(Optional<T> value) |
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=> value.Value; |
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/// <summary> |
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/// Compares two <see cref="Optional{T}"/> values for equality. |
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/// </summary> |
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/// <param name="left"> |
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/// The first value to compare. |
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/// </param> |
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/// <param name="right"> |
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/// The second value to compare. |
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/// </param> |
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/// <returns> |
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/// <see langword="true"/> if the two values are equal, or |
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/// <see langword="false"/> otherwise. |
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/// </returns> |
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public static bool operator ==(Optional<T> left, Optional<T> right) |
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=> left.Equals(right); |
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/// <summary> |
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/// Compares two <see cref="Optional{T}"/> values for inequality. |
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/// </summary> |
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/// <param name="left"> |
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/// The first value to compare. |
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/// </param> |
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/// <param name="right"> |
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/// The second value to compare. |
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/// </param> |
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/// <returns> |
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/// <see langword="true"/> if the two values are unequal, or |
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/// <see langword="false"/> otherwise. |
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/// </returns> |
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public static bool operator !=(Optional<T> left, Optional<T> right) |
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=> !(left == right); |
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} |
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} |
FiniteReality